In the 3rd Generation Partnership Project (3GPP) TS 36.211 which is an existing version of the Long Term Evolution (LTE) standard, a single layer beamforming technique is supported. In a conventional beamforming, more than 6 transmitting antennas are usually used, however, only four ports cell-specific reference signals are defined in the existing version of the LTE standard, and are adopted in practical application, and channel information of each antenna port is extracted by a corresponding cell-specific reference signals, therefore, it is impossible to acquire the real channel information of each antenna with more than 4 antennas configuration.
If the number of cell-specific reference signal is increased, for example if 6 to 8 antenna ports are used for cell-specific reference signals, then the overhead of reference signals will be quite great, and there will be a difference in real channel information estimated by uplink/downlink, so the beamforming weight-value feedback information is still needed to be estimated on the real channel information.